review 2

Errrr... obviously I just submitted the wrong one. Please disregard, this
is the correct one.

The Design Philosophy of the DARPA Internet Protocols

The internet is constructed using many layers of protocols and services,
but it is often difficult to see the over-arching design goals behind it.
The fundamental goals of the internet were to provide interrupted
communication despite equipment failure and to support multiple types of
communications and networks. To satisfy the first goal, communication
state for each connection was pushed to the distinct end-points, since a
failure at either end-point would mean failure in any case. If the
internet could then continue to send messages between end-points despite
some transient failures of intermediate gateways, end-points could
continue without having to deal with any of the intermediate problems.

To satisfy the second and third goals, basic assumptions about the exact
nature of networks over which the internet will operate were made as
minimal as possible, then a suitable building block (the datagram) was
selected. The splitting of TCP and IP was required but allowed the
different types of service that were required. These types of service
would be implemented by different algorithms at the end-points, since the
only network building block was the datagram.

This paper documents an interesting case of how particular design goals
colour the construction of a system. The explicit construction of a set
of valid assumptions allows for the construction of a system in a very
elegant way. However, A lot of the secondary goals seem to be very
vestigial. The basic assumption that the internet will operate over
networks that may only provide the ability to transport packets seems to
preclude (to some extent) the design goals of distributed management and
accountability.
Received on Thu Sep 14 2006 - 01:23:32 EDT